What is MIME type "text/x-assembly"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

text/x-assembly designates files that contain assembly language source code. It tells programs, text editors, and web servers that the file’s content is a text-based representation of low-level instructions written in an assembly language.

This MIME type is used primarily for assembling code that a computer’s processor understands. It informs software to apply syntax highlighting and proper text handling for better readability and editing.

Main use: Identifies assembler source code files.
Functionality: Helps development tools recognize and format low-level code.
Additional uses: Serves in build pipelines and code repositories where assembly code documentation is required.

Files with extensions such as S and ASM fall under this MIME type. They are processed as text, allowing for manual editing, debugging, and clear structure during development.

For extra technical details and updates on MIME types, visit the IANA media types registry.

Associated file extensions

.s, .asm

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: text/x-assembly

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="text/x-assembly">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'text/x-assembly');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.s, .asm

FAQs

What is the purpose of the text/x-assembly MIME type?

The text/x-assembly MIME type identifies files that contain Assembly language source code. It tells text editors, IDEs, and web servers that the content is a low-level programming script, usually intended to be compiled by an assembler.

Will a web browser execute a file with the text/x-assembly type?

No, web browsers cannot execute Assembly code directly. Because the main type is text, most browsers will either display the source code as raw text or prompt you to download the file to your computer.

How do I configure Apache to serve .asm files correctly?

To ensure your Apache server sends the correct header, add the following line to your .htaccess or configuration file: AddType text/x-assembly .asm .s. This helps client applications recognize the file as code rather than generic text.

Why does this MIME type start with x-?

The x- prefix indicates that text/x-assembly is a non-standard or experimental subtype not officially registered with the IANA. It is a widely accepted convention used by operating systems and developers to distinguish Assembly code from standard plain text.

Can I open text/x-assembly files with a normal text editor?

Yes, since the underlying format is plain text, you can open these files with any editor like Notepad, VS Code, or Vim. However, using a code-aware editor is recommended to get syntax highlighting for the specific assembly language variant you are using.

What file extensions usually use text/x-assembly?

The most common file extensions associated with this MIME type are asm and s. These extensions are standard for assembly source files across various architectures like x86 and ARM.

Is text/plain a valid alternative to text/x-assembly?

Yes, text/plain works as a fallback because Assembly files are human-readable text. However, using text/x-assembly is preferred in development environments because it allows tools to automatically apply the correct formatting and language intelligence.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.